Boot upper



FIG. 1 is a perspective view of my new design for a boot upper;

FIG. 2 is a side elevation thereof, the other side being a mirror image;

FIG. 3 is a top plan view thereof;

FIG. 4 is a front elevation thereof; and,

FIG. 5 is a rear elevation thereof.

The bottom view does not form a part of my design.

The broken line showing of the sole of the boot is for illustrativepurposes only and forms no part of the claimed design.

The ornamental design for a boot upper, as shown and described.